Method of producing malleable tungsten.



UNTTED STATES PATENT OFFICE.

ARMIN HELFGOTT, OF UJ-PEST, AUSTRIA-HUN GARY, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

METHOD OF YRODUCING MALLEABLE TUNGSTEN.

No Drawing.

To all whom it mayponcern:

Be it known that I, ARMIN HELFGOTT, a subject of the Emperor ofAustria-Hungary, residing at Uj-Pest, Austria-Hungary, have inventedcertain new and useful Improvements in Methods of Producing MalleableTungsten, of which the following is a specification..

Mechanically workable bodies of tungsten, for example, those which maybe hammered and drawn into wires, are, as is known, made by pressing drytungsten powder into suitable forms and sintering the articles thusobtained. The properties of tungsten bodies obtained in this manner, aswell as their behavior during mechanical working, are stronglyinfluenced by the character of the tungsten powder which is used as thestarting material for making the pressed articles.

If a very fine black or so-called amorphous tungsten, consisting of analmost impalpable powder, is taken to start'with, very good pressedbodies are obtained by pressing this powder, as the fine particles ofpowder adhere strongly. Ifthese pressed articles are sintered, however,there are apt to result bodies which possess a structure unsuitable formechanical working, since they consist of quite large crystals withlarge surfaces and consequently are very readily broken and fall apartin mechanical working by hammering. In consequence allowance must bemade in manufacturing for a great waste. Moreover, the fine blacktungsten powder always contains oXid. The contained oxid also appears tohave an injurious effect upon the properties of the product. If in themanufacture of the pressed bodies or sticks use is made of more or lessgranular (gray) tungsten, then other difficulties are to e reckoned within pressing it. The adhesion between the individual granules .is veryslight and consequently the pressed article possesses only slightstrength and breaks easily in handling. In the sintering process,however, such pressed articles behave better than those made of veryfine black tungsten; they preserve their fine grained structure whichhas'a favorable influence upon the Specification of Letters Patent.

Application filed July 16, 1913.

Patented Nov. 28, 1916.

Serial No. 779,268.

formation of fibers in the subsequent working.

According to the present invention an initial or startingjfiiaterial isemployed which combines the advantages of the materials above mentionedwithout possessing their disadvantages. To this end mixtures of granulartungsten with finely powdered tungsten are employed. In this case thefinely powdered metal performs, so to speak, the function of a binderwhich cements together the individual grains of the granular metal.These bodies therefore may easily be pressed and can be convenientlyhandled in this condition; in sintering the bodies likewise behaveadvantageously, and since the finely powdered metal. and the separatethe clear black changing over into a dark.

blackish gray, and at the same time the density increases without thefineness being perceptibly impaired. The fine grained blackish graytungsten powder thus obtained is very well adapted to perform thefunction of the above-mentioned binder during the pressing of thegranular tungsten metal.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,

1. The method of making tungsten bodies which consists in admixingcoarse grained tungsten powder and very fine grained tungsten powder,pressing the mixture of powder to form a coherent mass, and sinteringsaid mass.

2. The method of making mechanically workable tungsten bodies whichconsists in presslng into a coherent mass a mixture composed of granularpowdered tungsten and finely powdered tungsten, and sintering the mass.4

3. The method of producing tungsten bodies Which consists in heatingfinely pulverized tungsten in a reducing atmosphere to free it from oxidWhile maintaining its fineness unimpaired, making an admixture composedof said finely pulverized oxid free tungsten and of granular tungsten,pressing 10 said admixture to form a coherent mass, and sintering saidcoherent mass.

In Witness whereof I have hereunto set my hand.

ARMIN HELFGOTT.

